1. Field of the Invention
This invention relates to a homogeneous process for the homologation of methanol to acetaldehyde, ethanol or mixtures thereof. In one aspect of the invention, methanol is reacted with carbon monoxide and hydrogen in the presence of a catalytic system containing cobalt and ruthenium.
2. Description of the Prior Art
The production of ethanol from methanol, carbon monoxide and hydrogen in the presence of a cobalt catalyst and an iodine promoter and a ruthenium halide or osmium halide secondary promoter is disclosed in U.S. Pat. No. 3,285,948 (Butter). A similar catalyst system based on Co.sub.2 (CO).sub.8 is described by Metlin et al., Abstracts of Papers, 17th Spring Symposium of the Pittsburg Catalysis Society, April, 1978.
U.S. Pat. No. 4,133,966 (Pretzer et al) relates to a process for selectively preparing ethanol from methanol, hydrogen and carbon monoxide in the presence of a catalytic system containing cobalt acetylacetonate, an iodine compound as a first promoter, a ruthenium compound as a second promoter and a tertiary organo Group VA compound. In order to avoid a wide variety of other products and optimize the formation of ethanol, patentees specify cobalt acetylacetonate as the cobalt source. If selectivity to acetaldehyde is desired, U.S. Pat. No. 4,151,208 (Pretzer et al) teaches a process wherein methanol, hydrogen and carbon monoxide are contacted with cobalt (II) meso-tetraaromaticporphine and an iodine promoter.
It would be desirable to have a single catalyst system which can efficiently convert methanol to acetaldehyde or ethanol with a high degree of selectivity and without the formation of substantial amounts of undesirable by-products.